The stop follows a trip to China where Castro met with leaders and signed a series of economic agreements.

The Asian visits are seen by some Cuban watchers as an up-close chance for Castro to see Vietnam and China's mix of capitalism and socialism at work. The two countries have embraced market economy reforms and experienced rapid development, while Cuba has remained largely poor.

Castro last visited Vietnam in 2005 as defense minister, a title he held from 1959 until replacing his older brother, Fidel, as president in 2008.

Vietnam supplies the bulk of Cuba's rice imports, and bilateral trade stood at $274 million last year.